Late Weichselian glaciation and deglaciation in northeastern Troms, northern Norway

Abstract

The lower limit of block fields, weathering surfaces and the vertical distribution of erratics and glacial striation probably mirror the extent and the gradient of the Late Weichselian continental ice sheet in northeastern Troms, northern Norway. Nunataks plausibly existed in the area during the Late Weichselian maximum and the continental ice sheet had a low-gradient profile in the archipelago. It is most likely that the ice extended out to the Fugløybanken area, but that it did not coalesce with the Barents Sea ice sheet. According to an equidistant shoreline diagram (ESL diagram), the outermost coast of Arnøy was deglaciated between 16 000 and 15 000 BP. Calving in the Lyngen and Kvænangen fjords highly influenced the deglaciation dynamics. The coastal areas had local glaciers and permafrost conditions for a relatively long period of time (of. Sollid & Sorbel 1988, 1992). During both the Skarpnes and the Tromsø-Lyngen substages dated to 11 200 ± 190 BP and 10 350 ± 300 BP respectively (Andersen 1968), the ice front terminated at the inner, shallow part of Reisafjorden. The age of the youngest ice-front deposit, located at Bergskogen in Reisadalen, is estimated to be c. 9500 BP.